Improvement in vacuum-tanks for tanning leather



D. F. NOYES.

Improvement in Vacuum `Tanks for'Tanning heathen No. 123,192. Patente'dlan.3o,1e72.f

UNITED STATES PATENT OFFICE.

DAVID F. NOYES, OF LEWISTON, MAINE.

lMPRCVEMENT IN VACUUM-TANKS FOR TANNIG LEATHER.

Specification forming part of Letters Patent No. 123,192, dated January 30, 1872.

Specification describing a new andl useful Improvement in the Construction of Vacuum- Tanks for Tanning Leather and other purposes, invented by DAVID F. Nox/Es, of Lewiston, in the county of Androscoggin and State of Maine.

The object of this invention is to so construct tanks for tanning leather by-the vacuum process, and for other purposes, that they will be sufficiently strong When made of Wood, and tight enough to preserve the vacuum and it consists in one or more layers of pitch or cement of any suitable kind applied when in a iiuid state, so that not only every crack andcrevice in the Walls and sides of the tank will be' filled therewith, but so that the air shall be totally excluded from the tank; the tank being otherwise constructed, as hereinafter more fully described.

The accompanying drawing illustrates my invention.

The tank is constructed mainly of Wood, and may be described as consisting of two or more boxes, A, one Within the other, with spaces between for receiving pitch or cement C in a liquid or semi-liquid state. In this example ot' my invention three thicknesses of wood areshown; also, one layer or box, of metal, D 5 but I do not confine myself to the use of any metal in the Walls or sides of the tank, as, to be durable, the metal must be copper, or such as is non-corrosive, which is expensive, and may be dispensed with by the use of the pitch or cement which forms the main feature of my invention. E is the chamber Where the hides to be tanned are placed, and Where a vacuum is formed bymeans of a pump attached to the pipe F, through which the air is exhausted. G is the entrance to the chamber, and H is the cover. This cover is packed on its under side, so that the 'pressure of the atmosphere holds it tightly to the tank. It may be made of metal or materials which will enable it to stand the atmospheric pressure. The chamber E is usually made-about ten feet in length and width, and six high. The hides to be tanned are suspended by hooks or poles, so that every part thereof may be exposed to the action of the tannin. When the hides are thus arranged the air is pumped out and a vacuum more or less perfect is formed, and then the liquor is admitted through the pipe I by turning the cock J. The liquor is changed as often as may be found necessary. These vacuum tanks have hitherto been made ot' iron, but it has been found that the tannic acid combines readily With and oxidizes the iron and colors the liquor, consequently coloring the leather, and making it to a certain degree unsalable. Hence .I make my tanks of Wood to overcome this diiculty, and after various trials and experiments I have found that the vacuum cannot he preserved in a wooden tank except by the use of pitch or cement applied according to my invention, or without one or more continuous and perfect partitions thereof, surrounding the chamber on either side.

When the Wooden partitions, boxes, or layers are placed, and the exhaust induction-pipes are attached, the pitch or cement, in atluid or semi-duid state, is poured into the spaces, so as to entirely surround the chamber E with one or more partitions, layers, or coats thereof. This hardens directly, excludes the air, and preserves the vacuum, While it preserves the wood from decay.

I do not limit or confine myself to the precise form or arrangement of any of the parts described, as they may be varied in many ways Without departing' from my invention. Neither do I confine myself to vacuum-tanks for tanning hides or leather, but design to apply the invention to tanks for bleaching or extracting' tannin from bark by the vacuum process, and for other purposes.`

Having thus described my invention, I claim as new and desire to secure by Letters Patent- 1. A vacuum-tank for tanning leather, and for other purposes, composed partly of Wood and partly of pitch or cement, substantially as shown and described.

2. The chamber E, surrounded by 011e or more layers, partitions, or thicknesses of pitch or cement, substantialiy as shown and described, and for the purposes specified.

3. A vacuum-tank for tanning leather, and other purposes, composed in part of pitch or cement, said pitch or cement forming one or more continuous layers or stratums around the vacuum-chamber, and is itselfsurrounded With Wood, substantially as shown and described.

D. F. NOYES.

Witnesses:

T. B. MosHER, GEO. W. MABEE. 

